Calculating colon transit time with radionuclide-filled capsules in

Abstract

Background: Colon motility disorders require reliable methods for calculating segmental colonic transit time. This study evaluated bowel transit time by means of a safe, easy, cheap, nondigestive, and nondisintegrating radionuclide-filled capsule that provided accurate and clear images.

Methods: Radionuclide-filled minicontainers (MCs) were prepared from infusion sets by an apparatus used for sealing blood bags or plasmapheresis sets. In vitro stability studies were performed by immersing 5% methylene blue dye-filled MCs in buffers of variable pH and enzymes simulating the conditions in the stomach and the small bowel. Colon transit scintigraphy was performed with MCs filled with iodine 131 (n = 5) and thallium 201 (n = 8) that were placed in a commercially available capsule.

Results: By in vitro acid, base, and intestinal enzyme resistance tests, no methylene blue leakage was determined visually and by spectrophotometric analysis. Accurate and clear images were obtained for colon transit study in constipated patients. After excretion of MCs in the feces, abdominal, myocardial, thyroid, and urinary bladder region counts were found to show the same activity as the background. Radionuclide leakage from MCs was not determined in vivo by gamma camera.

Conclusion: This is a suitable, safe, easy, and cheap method to provide accurate and clear images for colon transit study in constipated patients.